How often should I empty my Bio-drum™?

With warmer weather creeping closer, thoughts of going to the cabin or cottage are probably starting to slip into the forefront of your mind. Thoughts of ‘where has my owner’s manual got to?’ and ‘do I have any Compost Sure left from last season, or should I stock up early?’ are not uncommon, but one question that our customer service department gets a lot before, during and after the summer season is, ‘Should I empty the Bio-drum™, and if I do, how often do I have to do that?’

This is a loaded question, and it’s not necessarily an easy one to answer depending on what kind of usage your toilet will see.

First and foremost: unless something like bleach has been put into the composter, or there has been damage of some kind to the inner mechanics of your Sun-Mar toilet, you should never have to empty the drum entirely. By emptying the drum of existing compost completely, you would essentially be wiping out your existing microbe colony and starting over fresh.

If your toilet has been well-loved and you’re just going up for the weekend until the spring thaw comes, emptying the drum is not necessary.

Each Sun-Mar installation is different, so there is no set-in-stone schedule for when you should remove compost from the Bio-drum™. That being said, as a general rule, you would want to remove compost at least once a month if your toilet is used residentially, and once a season if used occasionally or on weekends.

A general guideline for when to remove compost is the circular indent on either end of the drum, which you can see when looking inside the drum opening. If compost is halfway up that circular indent, removing compost from the drum would be a good idea to prevent the drum from becoming too full.

For information on your specific toilet, please check your owner’s manual, or contact our customer service department at 1 888 341 0782 ext 1018, or via email at

Bio-drum™ composting cleaning

**Please note: The information in this post is not intended to replace your owner’s manual. As each installation is different, if you have any questions, our customer service department is more than happy to help, and can be reached at 1.888.341.0782 ext. 1018, or via email at **